In 2003, the population of a city is 80,000 people, and is growing at a rate of 4% per year. a. what will the population be in 2015? b. in what year will the population be triple?

In thousands, the population can be modeled by
  P = 80*1.04^(t-2003)
where t is the year number

Finding answers to the questions can be done graphically.

a) In 2015, the population will be about 128,083.

b) The population will be 240,000 in 2031.

_____
a) p = 80,000*1.04^12
b) t = 2003+log(3)/log(1.04)

The length of what is left would be 1 1/2 feet long.